1. Field of the Invention
The present invention relates to motorized window shades.
2. Description of the Related Art
A roll-up window shade is well known. The shade can be moved manually up or down in front of a window to control the light level, room temperature, light flow, or to provide privacy. The known roll-up shade is relatively inexpensive and is easy to install. If the shade is damaged, a new shade can be replaced easily. These types of shades are sold in retail stores and do-it-yourself centers across the U.S. The shades are typically stocked in 3, 4, 5 and 6 foot widths. The shade can easily be cut to the proper width with a cutting device either at the point of sale or at installation time. The installer or homeowner can measure and install the shade on the same site visit.
The conventional roll-up shade has a first pin end and a second spring end with a rectangular barb extending outwardly. The pin end is inserted into a circular hole in a bracket. The spring end is mounted in a similar shaped bracket with a slot designed to keep the barb from rotating. The brackets are designed to be mounted inside a window frame i.e., inside the jamb, or along the outside of a window frame. The user pulls the roll-up shade down by a hem bar located along the bottom edge of the shade until the desired amount of shade material is showing. The user then eases up on the hem bar until the pawl mechanism in the spring end of the shade locks the shade into position. As the shade is being pulled down, the spring is being wound up.
When the user wants to put the shade up, the user pulls down on the hem bar slightly to disengage the pawl mechanism and then guides the hem bar upward as the spring pulls the fabric upward. If the user lets go of the shade as the shade is traveling upward the spring in the shade will cause the shade to travel upward out of control. The hem bar will continue to rotate around the roller until it stops. The setting of multiple shades at the same relative position can be a very time consuming process. The manually-operated shades are not capable of receiving inputs from time clocks, photo sensors, occupant sensors or infrared hand held transmitters.
It is known to replace the spring mechanism described above with a motor, typically a tubular motor, to allow the window shade to be rolled and unrolled (opened and closed) by remote control. Installation of these systems typically requires a skilled craftsman. The installer usually will need to make one visit to measure the window and another separate visit to install the system. In some systems, the hem bar located at the bottom of the shade travels in channels secured to the sides of the window opening, thus, decreasing the amount of light that can enter through the window when the shade is up. The motor is typically connected to a nearby power source with line voltage or low-voltage wiring.
A typical motorized roller shade is secured to the window opening with two mounting brackets. The single roller shade is custom made with a fabric of choice. The motor is installed inside the roller tube at the factory and line or low voltage wiring connects the motor to a nearby power source. If the unit fails, the unit must typically be returned to the manufacturer or a technician must visit the job site.
Multiple units can be grouped together by wiring the multiple units to each other or to a common control system. Installation of such wiring is beyond the capabilities of most homeowners, and thus, such units must be installed by a professional installer.
The prior art devices generally suffer from a number of disadvantages including the inability to communicate with other devices, lack of intelligent control, e.g. by a microprocessor, and thus, having inability to be programmed easily, bulky size causing difficulty in installation, an unattractive appearance and maintenance problems as well as inability to easily retrofit to existing manually actuated shades. These problems have severely limited the market for motorized rollup window shades.